//
// Created by 11510 on 2024/6/25.
//
#include <iostream>
#include <list>
#include <vector>

using namespace std;

std::ostream &operator<<(std::ostream &ostr, const std::list<int> &list) {
    for (auto &i: list) {
        ostr << " " << i;
    }
    return ostr;
}

void test1() {

}

int main() {
    test1();
    return 0;
}